This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This study aims to explore the ability of 5'disodium cromoglycate (5'DSCG) to induce crystallization of solubilized proteins.Previous studies revealed that 5'DSCG stabilized protein structures. In aqueous solution, 5'DSCG forms nonamphihlic assemblies that are highly hydrated in water. With its abilities to stabilize protein structures and to sequester water molecules, we propose to use 5'DSCG as an agent to induce the crystallization of proteins. Our hanging drop vapor experiments showed that 5'DSCG induced the crystallization of lysozyme at a concentration significantly lower compared to the amount required when sodium chloride is used. We would like to examine whether 5'DSCG gives rise to a different crystal structure for lysozyme. Furthermore, when we performed hanging drop vapor diffusion experiments of proteorhodopsin with 5'DSCG, we obtained rod-like crytals of about 150 um in size. We would also like to verify whether these rod-like crystals are diffraction-quality crystals of proteorhodopsin.